ᐅ Screed or tile adhesive

Hello,
I removed the old tiles in my hallway using a rotary hammer! However, I’m unsure about the light-colored floor underneath. Is that the tile adhesive or already the screed?
I plan to sand the entire area tomorrow!

The screed is light gray, and the layer of tile adhesive is not particularly thick. You should be able to see some residue of the tile adhesive under the tile.

Best regards,
Sabine

Hello "Marcel89".
Unfortunately, the photos are not very conclusive. In the second photo, it appears that a screed was installed on a separation layer. This is suggested by the thickness of the light-colored layer. Although cement screed would be light gray, as "Sabine" already mentioned, there have been and still are other screed binders besides cement!
The third photo, on the other hand, rather suggests that the tiles were installed using the medium-bed method at that time.
"As the saying goes, nothing is certain."
Check the average thickness of the layer.
If it is over 15mm (0.6 inches), it is likely a screed; if it is below that, it could be tile adhesive (possibly with leveling compound).
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Regards, KlaRa